Various heat treatments (e.g., hardening, annealing, normalizing, spheroidizing, tempering, etc.) are known. These processes can involve operations, or combinations of operations, involving the heating and cooling of a metal or an alloy in the solid state, for the purpose of obtaining certain desirable conditions or properties. Heat treatments, therefore, may be useful for generating a material having properties especially suited for use in a particular part, structure, or application.
In most heat treatment processes, for example, the desired material properties of a component are controlled/obtained by controlling the temperature of the component, the rate of change of temperature of the component, and the amount of time that the component spends at a certain temperature or within a range of temperatures. Adjusting the parameters of a heat treatment may result in a change in material properties including, for example, hardness, grain size, toughness, crystal structure, ductility, elasticity, density, optical reflectivity, electrical conductivity, thermal conductivity, electron mobility, magnetic susceptibility, carbon content, and porosity.
While known heat treatment methods may achieve acceptable results, some of these methods include several disadvantages. For example, some known methods employ traditional furnaces for heating the materials to be treated. Using these furnaces, it may difficult to precisely control the temperature of the material. For example, for a particular rate of increase in temperature within the furnace, there may be a corresponding lag in the temperature of the material. This lag may be significant, and in certain heat treatment processes, not all of the material to be treated may achieve a desired processing temperature or satisfy a desired time-temperature profile. This can lead to formation of undesirable phases within the material or to degraded material properties.
Further, some traditional heat treatment methods using conventional furnaces may not be suited for heat treating objects with non-standard profiles or shapes. For example, in conventional systems, any sharp corners or small fillets on a part to be heat treated may produce large stress concentrations during the heat treatment process. As a result of these large stress concentrations, the part may experience cracking or some other type of damage during heat treatment. Also, conventional heat treatment systems may not be suitable for treating unusually shaped parts having reentrant features, multiple different thicknesses, or variable cross sections.
The present invention can solve one or more of the problems associated with known heat treatments.